This invention relates to the preparation of shelf-stable, soft dough products such as soft pretzels, breads and cookies. The products of the invention can be provided in the form of fried or baked ready-to-eat goods, which have excellent shelf-stability.
One of the major problems associated with ready-to-eat dough products is their short shelf life. In order to compete with freshly made products, previously cooked and prepackaged dough products must be shipped to the retailer for sale before they begin to lose their original qualities of texture, flavor and moistness. Using previously available methods, it has not been possible to produce ready-to-eat soft dough products having a shelf life in excess of about 14 to 30 days.
Almost immediately after cooking, a dough product begins to lose its soft texture. Water activity (A.sub.w) is a major determinative factor in the shelf life of dough products. Water activity, which can be defined as the ratio of the fugacity of water in the system being studied to the fugacity of pure water at the same temperature, is a measure of how tightly a material binds water molecules. In other words, A.sub.w is a measure of the tendency of a material to allow water to migrate to the surrounding environment. A relatively high A.sub.w, i.e., an A.sub.w approaching 1.0, indicates a tendency to allow water to migrate easily out of the material. Thus, cooked dough products with high A.sub.w values tend to lose moistness and undergo textural changes within a relatively short period of time.
A.sub.w is a particularly important factor in product stability when the dough product is employed in contact with other materials such as fillings, toppings or materials applied topically to impart flavor or texture variety. For example, soft pretzels generally have salt deposited on their surfaces in the form of crystals which impart flavor and texture variety to the product. It is important that this surface salt maintain its crystalline integrity. If the A.sub.w of the soft pretzel exceeds about 0.72, water migration out of the product tends to dissolve the salt crystals on the surface. If the product is to be filled with a filling such as a jam or creme filling, it is important that the A.sub.w of the dough product and the filling do not differ by much, since differing water activities will result in water migration between the filling and the dough product.
Products having relatively high A.sub.w values also tend to be subject to microbial activity which further contributes to poor shelf-stability.
It is readily apparent from the foregoing discussion that the ability to control water activity in cooked dough products, particularly the ability to minimize water activity, is crucial to the obtainment of shelf-stable products. Sugars, such as high fructose corn syrup, sucrose, honey and the like, can be added to doughs in order to reduce water activity, thus prolonging shelf life. However, these sugars are high in mono- and disaccharides which impart sweetness to the product. High levels of sweetness are undesirable in many baked products such as breads and soft pretzels. Lack of shelf-stability of precooked dough products has made it virtually impossible for large-scale snack food processors to compete with certain fresh-baked goods low in sweetness, such as soft pretzels.
U.S. Pat. No. 4,456,652 discloses a method of producing ready-to-eat baked goods from a flour containing batter mix, water and at least 5% by weight of the product of an edible, liquid polyhydric alcohol. U.S. Pat. No. 4,511,585 discloses a similarly produced product, the primary difference being the ratio of flour to edible, liquid polyhydric alcohol. The water activities of the baked products are generally in the range from about 0.75 to 0.85.
U.S. Pat. No. 4,291,065 describes the use of certain sugars as anti-staling agents, including oligosaccharides having from two to three hexose or pentose units.